1. Field of the Invention
The present invention relates to a multi-dimensional optical cross-connect (OXC) apparatus having a multi-casting function both in an optical domain and in an electrical domain, and more particularly, a multi-dimensional optical cross-connect apparatus in which data which does not require signal reproduction or wavelength conversion is cross-connected in the optical domain, and signals which require signal reproduction or wavelength conversion are cross-connected in the electrical domain
This work was supported by the IT R&D program of MIC/ITA. [2006-S-059-02, ASON based Metro Photonic Cross-Connect Technology]
2. Description of the Related Art
In a conventional optical-electrical-optical (O/E/O) information process, i.e., electrically processing all information after optical to electrical conversion in each network node, problems arise, in that an electrical information process itself causes a bottleneck as data throughput between nodes increases, and a higher cost is incurred for the electrical information process that increases in proportion to the data throughput.
When transmitting data from a 1:1 protection ring to a 1+1 protection ring using a conventional ring network cross-connection method, a single signal input from a hub node has to be copied into two signals and transmitted due to the nature of the ring network operation method. However, this ring network operation cannot be implemented with the conventional ring network structure.
In addition, when data is transmitted from a 1+1 protection ring to a 1:1 protection ring, only one of the two input data input from 1+1 protection ring has to be transmitted to 1:1 protection ring. However, this function also cannot be implemented with the conventional ring network structure. In addition, another drawback of the conventional structure is that, even when two 1+1 ring networks are cross-connected, network failures simultaneously occurring in the two ring networks cannot be overcome.
In addition, a conventional method of implementing a multi-casting function with a signal copy function by using an electrical switch, instead of an optical switch, has problems, in that an electrical information process causes a bottleneck as data throughput increases, and a higher cost is incurred for the electrical information process that increases in proportion to the data throughput.
Furthermore, in the case of using only an optical multi-casting process, problems arise, such as a collision of wavelengths, which occurs due to the use of the same wavelength for data transmission between different ring networks, or signal deterioration due to long-distance signal transmission.